Nuclear reactor core and fuel element-therefor

ABSTRACT

A REACTOR CORE INCLUDING A PLURALITY OF METALLIC CLAD FUEL ELEMENTS WHICH INCREASE THE VOLUME FRACTION OF FUEL IN THE CORE. THE AMOUNT OF FUEL WITHIN THE CLADDING ALONG THE LENGTH OF AT LEAST SOME OF THE FUEL ELEMENTS IS MATCHED TO THE NEUTRON RADIATION TO WHICH THE FUEL ELEMENT IS EXPOSED. IN ONE EXAMPLE, TWO DIFFERENT DIAMETERS OF FUEL PELLETS ARE USED WITH CLADDING HAVING A CONSTANT INSIDE DIAMETER. THE FUEL PELLET DIAMETER IS LARGER IN THE UPPER AND LOWER REGIONS OF THE CORE AS COMPARED TO THE FUEL PELLET DIAMETER IN THE CENTER REGION OF THE CORE. A LAYER OF LIQUID METAL SERVES AS A BOND BETWEEN THE VARYING OUTER DIAMETER OF FUEL PELLETS AND THE CONSTANT INNER DIAMETER OF THE CLADDING.

M. w. DYOS 3 NUCLEAR REACTOR CORE AND FUEL ELEMENT'THEREFOR April 16,1974 2 Sheets-Sheet 1 Filed Jan. 5, 1.973

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FIGS.

AVERAGE I TOP OF CORE CORE HEIGHT BOTTOM OF CORE DEFENSWE PEBLICAIONUNITED STATES PATENT OFFICE Published at the request of the applicant orowner in accordance with the Notice of Dec. 16, 1969, 869 0.6%. 687. Theabstracts of Defensive Publication applications are identified bydistinctly numbered series and are arranged chronologically. The headingof each abstract indicates the number of pages of specification,including claims and sheets of drawings contained in the application asOriginally filed. The files of these applicatlonsare available to thepublic for inspection and reproduction may be purchased for 30 cents asheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Ofiice makes no assertion as tothe novelty of the disclosed subject matter. 7

PUBLISHED APRIL 16, 1974 A reactor core including a plurality ofmetallic clad fuel elements which increase the volume fraction of fuelin the core. The amount of fuel within the cladding along the length ofat least some of the fuel elements is matched to the neutron radiationto which the fuel element is exposed. In one example, two diflierentdiameters of fuel pellets are used with cladding having a constantinside diameter. The fuel pellet diameter is larger in the upper andlower regions of the core as compared to the fuel pellet diameter in thecenter region of the core. A layer of liquid metal serves as a bondbetween the varying outer diameter of fuel pellets and the constantinner diameter of the cladding.

